Time on Cornell University's SP supercomputer, offered through the federally funded Smart Node program, may be just what you're looking for.
Larger allocations are also possible.
The Cornell supercomputer comprises 512 nodes, each node having about the same computing power as an entire IBM 590 machine such as CCIT's Aruba. In most cases about 430 nodes can be used on a research project. How to apply The UA's portion of the program is managed by CCIT's Research Support group.