Using centre speakers as front speakers

I'm really liking the idea of a MTM (mid-tweeter-mid) style speaker for my front speakers.

Has anyone on here used three beefy centre speakers as the FL, centre and FR? I'm a bit space limited and floor standers are too big and I feel the average bookshelf is too small.

Anyway have many on here tried this? Obviously the centre speakers used for the front left & right speakers would be placed vertically. Can anyone see anything wrong with doing this? My setup will mainly be for home theatre however I'd still like to achieve good sound with music CDs in two channel stereo.

Thanks guys