By the way - EVS might be able to help you out, there. When I was shopping for my HMC150, I started at EVS, since I've been buying from those guys for years. When I asked them if I could rent an HMC for a day, to try out the workflow and make sure I liked it, they didn't have a "rental" model yet. But they told me I could unbox one, and use it for the day - free of charge - knowing full well I'd buy it after I tried it. Not sure you're relationship with EVS, but there's a chance they could help you out in a similar way.
At teh very least, ask 'em for a lower rental rate - and they usually oblige.