Maturion ( http://www.dcfan.net.ru/forum/showthread.php?t=1670 ) pointed me at a not before recognized release of gpspDC, a Gameboy Advance emulator for Dreamcast.
It’s based upon GPF’s work and has been continued by alex.
Grab the update and enjoy, many things do work a lot faster (but still not fullspeed).
PS: The illustration screenshot shows a commercial game in action and does not come from PDRoms. You are free to test the emulators with many many free GBA games which are freeware and directly available here. As homebrew games are usually coded in a “lighter” way there is also a big chance of having them playable in a proper and acceptable speed.