Think that a small mobile would still be a better and easier solution. I looked at the mid power setting of my Kenwood TM-V71A and it draws about 5.5 amps for 10-15 watts out and 13 amps for full 50 watts. I don't think you can do much better with a brick behind your HT...especially if you have both drawing from the same battery. And using an HT at full power for much more than a few quick QSO's is tough on heat. Mobile rig is built better for heat. And you would only be packing one item vs two. If you look at 2m only mobile rigs, you might find something that draws even less current than my V71A and possibly smaller...although you probably need to look through the user manuals to find mid power level specs. The one thing easier with using an HT is that you're holding the antenna and radio and can change directions quicker. But who's logging? Also look at the LiFePo batteries...they seem to be the preferred power source.