I'm cutting pretty much the same stuff as the original poster, not so much in the bigger range, but if my spine wasn't giving me sh!t, I'd get myself either MS441 M-Tronic or a Husqvarna 576XP Autotune. The 660 is fun until the weight and vibes start wearing you down, so my 066 pretty much stays where it belongs, on my logosol.
Since you've already got an MS361, it would be cheaper and a lot more fun to get that 361 ported! A ported 361 is going to do most of what a 460 could do, with a lot less weight and fewer vibes. Instead of leaving the 660/460 in the trailer until needed, you'll be running that ported 361 all the time! Instead of dropping a grand on a new saw you'll use for 10% of your cutting, you'll spend $250 and have plenty left over for bars, chains, women, and booze.