While I'd love to see it based on the, as of now, nonexistent RChop,I think the RC3 is really the iconic RAT blade. IIRC most, if not all, the SWAT and "agency" knives have been based on the RC3. It also strikes the best balance of EDC easy of carrying, and "real handle" ease of use. For color, I really like the idea of the tiger stripe camo (alternating blend of the OD and black coatings is fine), with black linen scales and the mint green liners. With the full sheath options of the MIL, including the foliage sheath. Oh, and make it the plain pommel.
For artwork, what about the ESEE artwork
But replace the "EEES" with PACK. Put this in place of the usual logo. Where RC-3 usually goes, maybe a simple "#" followed by your RAT pack number? Do the engraving in gold.
Second choice would be the same in an RC4.
Third would be the same in an Izula (probably can't get the logo on the blade), but in place of the normal Izula serial number, put "RAT #" followed by your RAT Pack number.