ARM MCUs in hobbyist-friendly packages (DIP, SOIC)
Given the general evolution of packages (in general, not just ARM) towards ever-smaller SMT, it's IMHO a good idea to get used to the idea that soldering an SMT into a DIP adapter board is potentially part of having access to many chips/parts in a means that's convenient to play with.

The adapter boards are pretty common items in the wild. I suppose someone could possibly offer adapter boards with pre-soldered parts, but the premium would have to be fairly high to make that pay, I suspect.

Alternate approach is to face up to spinning a board to play with a part, perhaps leaving a bunch of options open (toss in unpopulated pads and outside connections.)