For purposes of foundations:
Tampers come in hydraulic too, but they're not quite the same idea as the gas powered ones.
Here is a sheepsfoot vibrating roller. But... not hydraulically powered specifically.
This whacker style one is self-powered, but cheap.
(is it possible to retrofit a compactor foot whacker style to operate on hydraulic power? Hmmm)
This is a collection of tools that would do our jobs - looks like form preparation tools and forms themselves and screed and... Ooh, I want these to do our concrete work with! Put a longer bar on that power screed and we'd be in shape indeed.
I'm not having any luck finding a heavy roller. All of the single drum rollers I can find are self powered, and expensive.
But I did find a skid steer mounted compactor. Worth considering in a design sense.
My answer based on my current research in the local market is "no, I cannot find a heavy roller". I also doubt that such a roller will do all we need. It will not be capable of compacting down in our holes where we are filling and stabilizing our column footers with gravel. It will not have the thrust/stabilizing power that the whacker style jumping jack has or the vibration capability of the plate compactor. In fact, I don't think that such a lightweight roller would even press on the ground quite as hard as our foundation will! (less than 1000 pounds per square foot contact)
_compaction functionality maybe an omission in our 50 GCVS tools_
I'd like to say, we know better than to build on non-compacted earth fill. Without power tools, we're left walking around lifting and thumping hand tampers...
Which although it is doable, is the sort of heavy work that leaves people saying, You've GOT to be kidding me.
I think the earth and concrete tool set in kansas city will be our best best in this regard.