I feel its important to be realistic - SureFires are for those who use WeaponLights for their jobs, where the cost can be justified far more easily.
Perhaps the Lights and Lasers forum over at AR15.com would be a place to explore aftermarket switch options for the SureFire G2/G2L ?
Calvin is a great WeaponLight dealer able to give you a range of options based on your stated requirements and where possible within your stated budget range.My highest recommendation is to visit the industry section at AR15.com and look for Brightflashlights.
Then the XM Tape Switch TailCap is looking a more suitable option given the demanding environment in which it will likely be used.The G2/G2L is planned for a different project(s). I have been working on something for a couple years. What started off as a toy may end up being a demo-rifle for a police agency. Heck there is always a chance that I may end up using this rifle for more serious work. As it stands it is very configurable. It is like a Swiss Army knife, but a rifle. I think the tape switch gives me the most configure ability.
You will not get any appreciable IR from a 'white light' LED. You'll need an incandescent lamp (such as the P60 use by the G2), and even then a dedicated IR illuminator such as the SureFire M1 will perform better (depending on the usage requirements)Assuming I like the G2/G2L on the rifle, I am tempted to buy the IR filter for the G2/G2L. Any unexpected issues?
You will not get any appreciable IR from a 'white light' LED. You'll need an incandescent lamp (such as the P60 use by the G2), and even then a dedicated IR illuminator such as the SureFire M1 will perform better (depending on the usage requirements)