Dust/planetary disks around stars?

[Evil Dr Ganymede]

So, lately there's been some new info about the dust disk around Vega, which might have a planet in it. But I was wondering - has anyone ever detected something similar around M-type main sequence stars? I've heard of disks around sun-like stars (and more massive ones like Vega), but never of ones around low mass stars. Are they just impossible to detect? How big would they be - similar in size to our solar system, or much smaller?