Hi Chase, and welcome!

You have posted this in the Home Recording Forum, so when you say "mobile digital recording set-up" are you talking about something built into a vehicle or simply a wheeled rack of gear that can be lifted and placed in a van for transport to a recording location?

My "mobile" rig consists of a pair of Alesis HD24XR hard disc recorders coupled with a variety of pre-amps and montoring mixers, but that sort of system does not come in anywhere near $3K. You can indeed get 16 channels of pre-amps for $3K that will interface to a laptop, but putting that in the same sentence as the word "quality" is more difficult.

Does your "sufficiently powered" laptop have a FireWire port or an ExpressCard or CardBus slot? You can get 8-channel FireWire interface boxes that will daisy-chain to give you the 16 channels you mention, or you could get an 8-channel master interface unit that has expansion ADAT ports into which you could plug 8-channel pre-amp boxes with ADAT output.

Before comitting to purchase, one thing you ought to consider is whether you really want all 16 pre-amp channels to have the same sonic flavour. You haven't mentioned your microphones or the type of music you aim to record, but the availability of at least two different types of pre-amp combined with a good selection of different microphones adds greatly to your flexibility of what you can record and how it will sound. You are not going to get a huge variety with only a $3K budget, but you could consider 8 channels of transformer-input pre-amps and 8 with conventional electronic inputs.

Before making specific pre-amp equipment suggestions, it would help if you could tell us a little more about what you expect to record, what you have in your microphone closet and the type of laptop you intend to use.

Thanks for the response Boswell. 16-tracks is the high end of what I'm looking for, to be honest. I have a MacBook with 8GB RAM running ProTools to a 2.0 USB external. My mics include:

Audix:
1 x i5 snare mic
1 x D6 Kick
2 x ADX51 condensers
2 x F9 condensers
1 x CX212
Shure:
4 x SM57's
Sennheiser:
1 x e906

I have no audio interfaces, preamps or other hardware as of yet. My budget could go beyond $3K and I may need to suck it up and go with 8 mic pre's. This computer has and optical/analog audio-port, 2 x USB, Gigabit LAN, Mini Display Port, and MagSafe ports. It runs Snow Leopard.

I'm looking to record everything from hard rock to classical, depending. This set-up will be for a recording venture I'm undertaking for my own music and other bands where recording will be done in various non-studio locations. I'm not expecting studio quality, but don't want to skimp and mail it in either. I hope this info helps in your recommendations!
-Chase

Trying to record into your laptop with 16 and/or 24 simultaneous inputs can be quite counterproductive. You could utilize 2 FireWire inputs and therefore get yourself a couple of 8 input FireWire interfaces. But that's assuming, your laptop has a FireWire interface? And each one of those devices will run you approximately $500 which seems to be within your budget. It'll even come with its own software which will be unnecessary since you have Pro Fools 9. But as suggested above, an ALESIS HD 24 with 2 banks of 8 microphone preamps would be a rocksolid advantageous way to go. You then just dump that recording into your laptop with Pro Fools 9 and take it from there. You can even utilize an HD 24 as a 24 input analog to digital converter and back again for Pro Fools 9 given the right external optical interfaces on a desktop machine. All of this can fit into a small rack box and be completely portable. I just happen to have my rack box on wheels and it stands 4 feet high. I also have a smaller box that's only 2 feet. And a secondary two foot box. You see I also have a rackmount 24 input mixer for monitoring & reverb & CUE sends and for developing a live reference 2 track mix without the need for a computer to screw up. I also like to utilize compressors and/or limiters on certain instruments and/or vocals while tracking. That's the technique that I use. In a sense, it's a miniature version of my control room in a box. While my control room is also in a box and can be seen at CROWmobile.com . Of course it's a 25,000 pound box requiring a Mercedes turbodiesel to move it. And it's much tougher today getting clients to pay for the diesel fuel than it was 20 years ago when I started this thing. Remember? That's when diesel was cheaper than gasoline and gasoline was cheap.

"Will work for food" Should be the new name for my company.
Mx. Remy Ann David