Socket AM3+ Mini ITX Motherboards. Why don't they exist?

I've been thinking of getting a Bitfenix Prodigy so I can keep my Athlon II x4 and one day upgrade to the best Piledriver CPU and all have to do is go from a AM3 ATX to an AM3+ Mini ITX Motherboard and have that be my last AMD machine, (unless I need a NAS or AMD pulls another Atlon 64 and actually makes the fastest CPUs) but the only problem is Mini ITX AM3+ Motherboards don't exist!

I guess I'll have to save my Pennies for Intel... I have nothing against Intel, I just like the freedom that AMD gives you with upgrade paths.

Why dont they exist I dont know I know asus made one for a little while but they are hella hard to find. its mostley because the am3 and am3+ sockets take up so much space its a challenge to find the room on a mini itx mobo. 

http://www.asus.com/Motherboards/AMD_AM3/M4A88TI_Deluxe/

Thats the only one ive ever heard of hope it helped!

That's an AM3 Motherboard, not AM3+ and I can't just keep my Athlon II x4 for a year or two and get a Piledriver later on and stick it in there.

Ah as it is well I dont really know then M-atx is the closest to it 

The AM3+ socket and boards came out in a time where SFF systems were not a thing. On top of that the NB chipset is still on the MB for AM3+ as well as its predecessors. It's not just the socket that's large - it isn't really - it's needing room for the NB and SB chipsets and VRM that leave space highly constrained especially considering you say you want the best Piledriver CPU eventually. The VRM requirements of the FX9590 are excessive to say the least, few motherboards even support it all full-ATX. It's not impossible, I mean AsRock made a m-ITX X99 MB and ASUS did that daughterboard VRM on one of their m-ITX, but it's impractical with AM3+ having been out so long and AM4 on the horizon. Also consider that last bit of info for a moment. The best Piledriver CPU right now is rather heavily outclassed and the single-core performance of the A10-7870K is about 25% better, but with half the cores and price. I say that owning both and an 1100T. If you can hold on to upgrading maybe a year longer, hopefully less; AMD's next CPU - Codenamed: Zen - should be out early next year. You can either get whatever floats your boat then, or get the A10-7870K and an FM2+ m-ITX now. Or even jump ship entirely to Intel.