I ordered an EverDrive flash cart as well as a couple of reproductions.
The flash cart has arrived, ordered on Thursday evening last week and came today. Which is amazing when you consider Friday and Monday were bank holidays in the UK.
Works perfectly so far.
The SD card full of ROMs is a bit hit and miss with what works. It doesn't help that my Mega Drive has been region modded and changes between PAL, NSTC and J-NSTC when you hold the reset button down. So I have to select the appropriate ROM for the region my console is set too. Some of the ROMs just don't work but that's the same with most "complete" sets. Apparently the ROMs that have been verified have in the title and that seems to follow what works and what doesn't.
On as side note, I've hooked up my Mega Drive to a Yamaha RX V375 5.1 AV receiver via the AV outs on the Mega CD. I have to say Streets of Rage II and MUSHA never sounded so good.