We had CatIIIa approach capabilities on the SAAB2000 with a HUD when I was in Europe. Hand-flown. Any real business jet going to Europe needs at the very least Cat II approach capability, which is not hard to get with the CRJ. Cat IIIa is also pretty nice to have and I can think of at least one time when Cat II would not have been adequate. Landing at CDG and called the RWY in sight very near the 50 foot DH.

Anyway, there might be some conversions to biz jet status, but probably not too many.

Also, yes, the system we had gave aural "Idle" and "Flare" cues.

One more thing... The SAAB2000 was vastly more stable and speed control was easier than on the CRJ. It is hard for me to imagine a Cat III approach in the CRJ hand flown. And another thing! They were serious about keeping planes and vehicles out of the ILS sensitive area there. The CatII/III line was much further back than the ILS sensitive line in the US. I once almost had to go around here in ORD because something cross the ILS and we lost the GS. Had we been lower I would have had to go missed. Anyway....