That's solid dude, although you'll be giving up a lot of height playing Elton Brand at C. I don't know which platform your on, I find it hard playing with a really small frontcourt, because even though they are strong, sometimes it's hard when you get outrebounded by 7+ footers like Yao, Dirk, Kevin Garnett, Tim Duncan etc etc.
And yes, I often play players out of position, it really depends on who I have.
Some guys who are regularly shooting guards I'll play as small forwards, eg - Michael Redd, Jason Richardson, etc etc. As long as they aren't giving away too much height it works.
And if I have a big SF who's got a great mid-range shot, I'll play him at PF and let him spread the key with jump shooting. It especially works if they are quick and athletic because they crash the boards, such players include - Gerald Wallace, Josh Howard etc.