There is interest from DLR-5 on coming up with an replacement tac-vest, but the problem is the 'Integrated Soldier System Project' (ISSP) will be coming online around the same timeline as an interim tac-vest would be fielded, so you've got to deconflict the projects.
Also, it's pretty much a given that the defence budget will likely shrink over the next few years, so given a smaller budget, where's the money going to come from to replace the vests?
This would fall into the capital acquisiton area and I don't think that the CLS is going to strongly support that ADM Mat takes some 30 Million from the Army's acquisition budget (original Tac-Vest contract was for $20 some million...you've got to factor in the increase in price if the pouches are modular this time around). CLS is/will have to be doing a massive balancing act in terms of what are need vs. want type equipment. He needs a LAV rebuild program, a Leo II Canadianization upgrade (or upgrade to Leo2A6 standard?) and ARV variants, a replacement for the 60mm mortar (CASW), a Light Armoured Patrol Vehicle to replace the RG-31 and G-Wagen C&R, etc. but also has programs that wants, such as a tac-vest replacement, Temperate Combat Boot (i.e. CADPAT boots), a Close Combat Vehicle, etc.
Given that ISSP is already on the books in terms of funding allocation, and that there is an in-service tac-vest that works for the rest of the Army that isn't combat arms, I'd say that an interim tac-vest replacement for the entire Army is likely a very low procurement priority in the grand scheme of things. Not to say that a UOR for a replacement vest couldn't/wouldn't be done for deployed ops though. However for an Army wide issue of a replacement tac-vest, Treasury Board would likely have a hard time seeing enough separation between the current tac-vest, an interim replacement tac-vest for the entire Army, and ISSP to allocate funding for the interim vest.
Now what could be done is to have additional monies being put into ISSP to provide a 'modular ISSP chassis' and 'modular non-C4ISR specific pouches' for the entire army which would be a defacto tac-vest replacement, so they can plug and play the ISSP specific C4ISR components as required, but this would require a significant revision to the current ISSP program's procurement and fielding plan.
However a problem with the approach of a single modular chassis for the evolution of ISSP is that the program is designed to have 3 fielding stages, whereby over time, 3 different ISSP evolutions will be fielded, replacing the prior version. If you've got a vest in widescale Army issue that was designed to work with the Gen I ISSP kit, and when you go to field Gen II ISSP, if that vest isn't compatible with the C4ISR components (which is really the nuts and bolts of ISSP), then you've got to replace the vest that the entire Army is using again, and possibly for a 3rd time with the Gen III ISSP. Pretty easy way to balloon costs to the point where a program runs seriously over budget.
In order to keep a 'low risk' approach to ISSP, it's likely that only enough kit (including vests and pouches) will be procured for that generation of the system.
In respect to UORing a bunch for deployed op, Afghanistan is pretty much over in 2011 (despite what people say we're going to maintain an OMLT or PRT, given the current political winds in Ottawa, right or wrong, I doubt that we'll maintain much if any of a force over there after our current mandate expires), so any UOR 'Try and Buy' type programs will have to happen before TF 1-10/3-10 get deployed (given government procurement speed, it's TF 3-09 has already passed beyond the needed timeframe), and would probably be limited to a single TFs worth of kit.
Even with a limited UOR purchase of CADPAT AR modular vests/kit, what does the rest of the non-deployed force do? -Stay with the current vest.
I'm speculating that the tac-vest will eventually be replaced, but by whatever iteration of a vest/rig that ISSP comes up with, and from the preliminary numbers put forth, they're looking at an initial purchase/delivery of about 3 TFs worth of kit in the 2011/12 timeframe, with numbers increasing to about 6-9 TFs worth of kit by the time that ISSP Gen III is fielded in the 2019/20 timeframe. Again, the tac-vest will continue on in service for those non-ISSP equipped units, unless ISSP's plan is changed to what I described above to include a modular chassis with non-C4ISR specific pouches to be issued to the entire Army as part of the initial fielding of ISSP Gen I.