My reverse lens setup and Homemade Wimberley Bracket.
As far as lens mounting you just need to purchase from ebay or other sources either a reversed lens mounting ring or a reverse lens coupling ring for lens stacking, they are very inexpensive and allow you to reverse a lens onto your camera body or onto the front of another lens.
Here is my setup, I shoot both reverse lens and stacked lenses so the length of the lenses that I use varies depending on which setup that I am shooting with. The flash bracket that I use is very versatile in its ability to extend the flash head to the end of the lens allowing me to use low powered manual flash settings. This is important, many people are surprised that I can get clear shots handheld at high magnifications, I really believe that this is more a function of the flash than it is my ability to hold the camera still. I believe that it was in Lord V's blog which is linked at the beginning of this forum that I read that the intensity of the flash is not a function of the intensity of the bulb during the firing of the flash, but it is a function of the duration of the flash, so the lower the flash setting the less time your subject will be illuminated enabling you to better freeze motion. Getting the head of your flash unit out to the end of a reverse set up means that it is only a few inches away from your subject allowing for very low power settings. For that reason and the instantaneous recycling of low powered flash settings I find that the bracket is very important to a good equipment setup. There are other commercially available brackets that will serve the same purpose, the Manfroto 330B will support two flash heads, is very adjustable and can be purchased for about the same price that I paid to construct my bracket.
My bracket is a homemade knock off of the Wimberley F-2 Macro Bracket that can be purchased for about $170.00 at either Adorama or B&H. If money is not an object for you the easiest route is to purchase the manufactured bracket. I chose however to build my own and priced out component parts this morning and it came to about $62 not including any shipping costs... some vendors offer free shipping and other's do not. Below I have listed the component parts that were I making this bracket a second time I would purchase, the only difference that I would make is the ball and plate that mounts to the straight flash bracket as I would use a diamond plate with two screws to secure it, I used a threaded stud that mounted directly to the mounting screw that came on the bracket, but it was very difficult to tighten enough to stop movement caused by the weight of the flash extended on the bracket's adjustable arm. All these components are made of Aluminium and are very strong, you can purchase some of these components made from plastic and save a little bit of money, but I like the idea of a strong arm holding my much more expensive flash head.
I am very new myself to reverse lens photography, but I will share with you some of the issues that I am still trying to overcome, the biggest challenge that you face will be positioning the flash head correctly so that you best balance the light as it is directional and it will be imbalanced, I try to position the diffuser so that I get a fair amount of light going both down and out away from the camera to try and balance as best as I can... The second thing that you will fight especially with just straight reversed lens more so than when lens stacking is flare, I try to keep the flash head behind the lens as best as possible, and have learned that if the flash is bouncing off a light colored shinny leaf, that I will have a problem with flare more so than if there is no reflection of the light, ie a bug on a stem where the light does not reflect.
From the Mount Depot
http://www.themountdepot.com/category_s/545.htm2ea Ram B-201U Double Socket Standard Sized Length Arm for 1 Inch Ball
1ea Ram B-230U Double Ball Connector with Two 1 Inch Balls
1ea Ram B-237U 1/4"-20 Male Aluminum Camera Stud with 1 Inch Rubber Ball
1ea Ram B-238U Universal Aluminum Diamond Plate with 1 Inch Ball Dia. Rubber Ball
From Amazon... Straight flash bracket.
http://www.amazon.com/dp/B007ETWWCO/ref=asc_df_B007ETWWCO2222448?smid=A33F2GQRYJ4V7X&tag=dealtmp655980-20&linkCode=asn&creative=395105&creativeASIN=B007ETWWCOThis is not the same straight bracket I purchased but honestly I do not see any difference, mine is 1/4" thick which I think is important, it is much heavier than many other straight brackets on the market which I think is important as I think that a thin bracket will probably flex due to the pressure that a flash mounted to what amounts to a torque arm will place on it. I ordered mine directly from China and had to wait weeks for delivery, this like I said looks to be the same bracket available on Amazon.
50mm reversed onto a 180mm lens, upto 4.6X magnification
Bracket easily extends out to front of this very long lens.
Ice Cream Box/Paper Towel DIY Diffuser front view
Ice Cream Box/Paper Towel DIY Diffuser side view