I've slowly risen above the stock soundcard inputs as well but instead of going with only what I only needed (2-4) inputs, I went for overkill and haven't regretted the leap one bit. In for an penny, in for a pound, right? My logic is you can never have enough inputs. I consider the extra inputs as redundant "backups" if any pres go south.
I have been delighted with the Presonus firepods. They're one-space rack mountable. All input cables plug into the front for easy accessibility while hiding your "fixed" output connectors in the back. The Pres are absolutely great and they have been solid for the 1 year I've owned the unit. They are very flexible in what input connctor types they receive in the front. What I think is genius about their design are the neutrik connectors on the front accepts both XLR OR 1/4" (mono or stereo) in the same connector, which covers all my varying input needs in my hobby studio. However, for output monitoring options, the firepod covers intermediate signal output routing at best. If you only need to have external monitors and outputs to a headphone amp and PA, then this will suffice just fine. I had to buy a mackie 6-channel headphone mixer amp to consolidate the firpod's monitor out complexities. I had some bands come over to track live where they needed a "gourmet-style" individual heaphone mixes for 4-5 guys tracking at the same time. Still, the firepod filled the need while only requiring one external piece of equipment needed to accomplish this.
http://www.presonus.com/firepod.html
Presonus unleashed a new product recently called the FireStudio which is supposed to have even better preamps than the FirePods already clean pres. The Firestudio also touts a robust software input/output signal routing capability against it's Firepod predecessor, which is what I needed to address the gourmet heaphone mixes. $699 for 8 class-A preamps just can't be beat, IMO. They're a beautiful mix of quantity AND quality.
http://www.presonus.com/firestudio.html
Hindsight being 20/20, If I knew the firestudios were on the horizon, I would've passed on buying the 'Pods and just leapt into the Studio version.
For a one man show, all the above should suit any of your needs just fine unless you're wanting to track a whole band live....then go with the Firestudio if that's in your plans.
As far as rack-mounting, you can go the DIY route if you have that sort of time and woodworking skill but since I don't have either, I picked up a 20-sp. studio rack at GC for like $99.00. You get double the space in a "studio rack" as opposed to a similarly priced "mobile rack" cases and they just look so much more professional than any of my past DIY attempts.