Just a heads up to you guys waiting for an Aridus front end - I ordered Feb 5. and received it today on Feb 26. Well worth it. Extremely well made, solid, and changes the feel nicely up front.
Also to continue the light mount discussion - You can mount a Magpul cantilever light mount in one of the front slots on the Aridus and if you have longer arms, you can easily reach a tailcap or flip switch like a TLR.