There are several cable throttle bodies that will bolt right on, MP has a direct fit part and there is an FAST adapter usually seen on ebay that allows an ls1 TB to bolt on.

The issue then becomes 'which pcm do I use?', because drive by wire was the only thing used in production....if you want to use a stock computer, you're also stuck with drive by wire.

So, converting to a cable operated throttle body means also converting to an aftermarket pcm. There are plenty of them out there to choose from that will all work fine, but not all of them have an off the shelf harness. If you want to modify the engine and need tuning capability, consider that approach. Usually after a guy has sent his stock computer out a few times at $400 bucks a pop, this option starts to look good.

Staying with the drive by wire and production style pcm creates another potential issue not brought up yet....what trans are you going to use? If the trans requires throttle pressure/kickdown input from the throttle, then check out the Bouchillon setup/'03 DR based pedal assembly (it isn't on their website, call them up).

'03 DR pedal assembly uses a short cable connected to a black box which then sends signal to the TB. All other years and models don't have the cable or other moving parts, and could be used with mtx or applications that don't need throttle pressure/KD linkage....the extra moving parts of the '03 truck setup makes for a handy place to set up a kickdown cable for the trans.

I'm not a naysayer and I like FI, you can do this any number of ways depending on what makes sense to you...
But I have to say I'm also partial to a carb setup because it reduces the cost and complexity so much. You get a carb which you probably already have, an intake, msd box, msd harness, and you're done...it runs, and you can set the timing and fuel anywhere you want whenever you want instead of sending the OE computer out and hoping they get it right which does not happen every time.