For film and video dialogue work, I'd agree that the ME64/K6 and ME66/K6 mics are pretty good. Durable, unaffected by weather, and a nice hot signal. I'm much less enthusiastic about using either combination for nature or ambient sound recordings. They just don't have a very natural sound and can sound a bit harsh and thin. With voice work, you can overcome this with some EQ--at least to some extent. For nature/ambient, I just don't think these mics are a good fit. At least I've never been happy with that application because of the unnatural coloration of the recordings. A lot of people go with the K6 combinations because of the self-powering, but with the MixPre, you have more options with the phantom power. Maybe a matched pair of Oktava MK012's. You'd need shock mounts and Rycote baby ball gags, but you'd still be well under $1K. The Oktava's aren't as sensitive as the ME64/K6, but with the MixPre, I'd think you'd be fine.