Hey
Where are you based? I know for the UK Maplin is a good supplier of enclosures, and they have a wide range. Depends also on how many sockets you have on your MegaDrum, and how good you are at working in small cases
I opted for a small enclosure, and tried to fit 32 jack sockets and a heavy duty USB connector, and I regret it! Just make sure you have plenty of room to work in, and do your best to get a quality case that wil protect it, the obvious really
just run an internet search in your country for 'hardware enclosures' or try and find one that will ship overseas!
Hope this helps.