doug, try this site, lots of pics just scale it up
http://www.transoniq.com/images/other.html
these look like cut down 5 gallon buckets
i got patterns for gallon jug feeders and pick nic table that make the rodent set to the table to eat,
another a tractor with corn cob stering wheel rodent sets at the wheel to eat
hope this helps
if this dont do google on guinea pig wheel,