I’ve seen some people do similar things using Google Voice. Your callers would call a Google Voice number and then you have some control over where it rings, you may be able to even listen in to the voice mail to screen the call and answer anyway (stealing them back from voicemail like an old-school answering machine).

One confusing thing I’ve heard about this setup is that Google Voice would be your voicemail, but in rare circumstances a caller might end up at your cell provider’s voicemail. This might be undesirable because you might not want them to leave the message there, might never check it, etc.

If you commited to such a scheme, you could transfer your existing number to Google Voice, and then get a new one for your cell phone. You should have some latitude in terms of how you want to route calls (i.e., you could set some numebrs to ring straight through to your cell phone, others would go to voice-limbo ring back, others would never get through, etc.).

I’m not an expert in this type of thing, but I know a few people who use rather exotic setups like I’m describing and seem to like them just fine.