My Model 1 Genesis + 32x + Sega Everdrive combo happily sits on prime shelving space in ym game room TV stand, just underneath my CFW Sony PS3.
I've got a Model 1 Sega CD. On top of that sits a Model 1 Genesis. On that, there's a 32x. In the 32x is a Neo Myth MD cart with an Neo2SD. In the Neo 2 SD is an SD adaptor containing a microSD card. It gets a bit ridiculous, but it can do just about anything. The only real problem is that it can't play SMS games with the 32X attached, so there's a bit of swapping. I just need to hook up a 2nd Genesis or get a master system flash cart.
I keep the 32X on the model 2. I have another 32X I sometimes put on the CDX for testing, but I normally leave it off so I can use the CDX for SMS games. I also have the SMS mod on my Nomad so I can play SMS games on it, too. The Nomad + SMS mod + Neo Myth/Everdrive == great portable fun!
If you are playing SMS games via flash cart on the Nomad, there's no difference between the Myth and ED since the Nomad doesn't have the audio line inputs on the cart port, so the Myth's YM2413 FM chip for SMS mode can't be heard on the Nomad. Oh well...
A flash cart is great for those super rare 32X games, like DarXide or the protos like Virtual Hamster and X-Men. There's a little 32X homebrew (mainly by yours truly ), including shareware versions of Wolf3D and Spear of Destiny, Rick Dangerous (full version), and a few demos like Yeti3D, and MOD player, and (just recently) an ogg-vorbis player.