The original R4 is also gone, after years of availability at 7 €, and so is the premium alternative (DSTwo)
That leaves 2 reasonable but inferior choices: the TTDS (with YSMenu) and the Acekard (with AKAIO, what Wood is a port of)
The shit flashcards (anything with R4 in the name except those 2 above, pretty much), including r4isdhc.com and r4i-sdhc.com, can also run YSMenu for decent compatibility and no timebomb, but no kernel can fix poor hardware quality
I think the Mister is cool and all, but honestly I have seen some video's exploring the difference between hardware and software emulation and the advantages of both.... I would pick software over FPGA, wouldn't mind some sort of hybrid approach but I can only imagine how complex that would be and how expensive.