While working on an unrelated project I acquired a copy of Jane's Naval Construction and Retrofit Markets, which contains a section on concept ship designs. The first section was Canada, and contained images and descriptions of some concepts from Saint John Shipbuilding, the prime contractor for the Halifax class frigates. These concepts date from the mid 1990s, as the Halifax program was winding down. I don't have much information on them, but I would speculate that they were private ventures intended for export, though they might have been offered to the Canadian government.
"Offshore Missile Corvette"
Displacement: 1,250 tons
Length O/A: 81.7m
Beam: 10.2m
Draught: 3.2m
Propulsion: 4x 5,920 kW diesels, 2x shafts w/ 5-blade controllable pitch propellers
Speed: 32 kts
Range: 4,000 nmi @ 16 kts
Crew: 63
Sensors: Unknown search radar, possibly TRS-3D; unknown hull sonars, 2x Ceros 200 FCR
Armament: 1x 76mm Super Rapid; "silos with 12 surface to air missiles" probably 6x bulkhead mounted Mk 48, 6x each side, with NATO Sea Sparrow; 4x Harpoons; 1x Phalanx, oddly placed; 2x Mk 32 SVTTs; 4x 12.7mm machine guns
Aviation: Helo deck and hangar for 1x Lynx or Seahawk sized helicopter
"Multi-purpose Fast Frigate"
Displacement: 2,800 tons
Length O/A: 105.8m
Beam: 13.9m
Draught: 4m
Propulsion: 2x 21,000 kW gas turbines, 2x 2,240 kW diesels, 2x shafts w/ 4-blade controllable pitch propellers
Speed: 33 kts "(plus)"
Range: 7,000 nmi @ 18 kts
Crew: 106
Sensors: Smart-S Mk 1; LW-08; hull sonar (appears to be SQS-510), 2x STIR-180 FCR
Armament: 1x 76mm Super Rapid; "combination of 16 VLS SM2s or Sea Sparrow SAMs" probably 16x Mk 41 VLS; 8x Harpoons; 1x Goalkeeper; 2x Breda 30mm single mounts w/local fire control; 4x fixed lightweight torpedo tubes; 4x 12.7mm machine guns
Aviation: Helo deck and hangar for 1x Lynx or Seahawk sized helicopter
This one is interesting for how much equipment and performance it would allegedly have. It has the same combat systems and most of the same armament of a Dutch M-Frigate, but with 16x Mk 41 instead of 16x Mk 48, two additional 30mm mounts (and heavy ones at that), 33 knots, and a smaller crew (by about 50) - all on a hull some 500 tons lighter.