+1 on the CDM1250, or in my case CDM1550LS+ as I already had them. Since you are experienced with radios, commercial gear will server you very well at the power you want (50W). Although, I also use a Radioddity DB20-G mobile as a base and as a mobile. Had to get two as they work pretty well for price and size.
Went with a new vehicle and stacked VHF/UHF Vertex VX-3200's would not fit the new car, DB20-G would fit into dash like it was meant to be there, so it is my mobile. Liked how it worked and programmed, so got one for base station. However, already had little portable power supply with radio stacked on top, made of Motorola CDM1550LS+ and another with XPR5550e mobile, which do work a lot better, just larger and heavier when moving around.
For oil industry I used to make a lot of mobiles attached to power supply as portable base station good for 45-55 watts in UHF/VHF....many ended up in hurricane response trailers, staging sites, and command posts. Good luck on making a GMRS base station, and in my own opinion, for base station use, I always try to get a desk mic.....as it just feels better than the mobile mic for use in vehicles. That makes the radio "feel" like a base station.