I believe the 1 MB ROM sample set has already been extracted and converted to the *.SF2 format (should be easy to find via a Google search).

However, the DOS based *.SBK files don't contain the full sample set (as most of the samples are stored in ROM).
Only the MT-32 & GS *.SBK files contain a couple of additional samples for remapping the standard General MIDI sample set.

As I recall, Vienna Soundfont Studio, that was included in the software bundle of most AWE cards, can open *.SBK files and save them as *.SF2 files.
Another application that can do this is Awave Studio.

How accurate the conversion is, is something that I haven't tried myself.

I'm actually looking for an application that can reliably convert *.SF2 files to *.SBK but, I've yet to find such an application. I also get the impression that the later format supports additional features that is not supported by the original format.

Just a shame that the DOS based Aweutil cannot read *.SF2 files...

Now that you mention it, Vienna Soundfont Studio does actually allow this, but it seems that in order for the files to be playable under Coolsoft MIDI Synth, the instruments in the Soundfont that refer their samples to "ROM Sample Pool" have to be changed to extracted and imported samples from 1MGM.SF2 in the "User Sample Pool. However, this appears to be a rather time consuming process.

Well I took the time to (messily) convert SYNTHGS.SBK by converting it to sf2 using Vienna Soundfont Studio, then merging it with 1mgm.sf2 using Viena (with a single n). Beyond that point, It indeed becomes a very painful process of changing the ROM samples used in the presets to the ones present in 1mgm, one by one.

I wonder if someone could write a converter to automate the process, since every ROM sample needed by the SBKs is present in 1mgm.sf2...