It'll take some time to get that, then. It would be helpful if you have a SS or HG and one of us can clone it there (I hope to get an Action Replay sometime, need one that works with 3DS and not in stores in Canada yet), and if you'd like you can also send a clone to Gen. V to trade back to me there if possible. It will take me a little time to get to Latios tho...I'm about halfway through the game not counting the Red Gyarados (Ecruteak Gym defeated). Going to train on Routes 42 and 43 to get to the level I need to in order to challenge that thing, then False Swipe it to capturability.
I don't have Latios or Carnivine yet, unfortunately. I have yet to get finished playing SS and, even if I were to do a Latios trade, it would be for data only. On the other hand, Carnivine I could trade for keeps once I get a couple with the Sinnoh Sound in SS (by which point I would be able to trade them into Platinum, which will be the game on the older DS, which will someday be importing to Black), but that is still a couple of gameplays away. I'll be doing Pearl/Platinum trading back and forth to complete the job quicker for those ones.
I might actually have a trading sequence set up to get the Porygon-Z and all data for pre-evolutions without breeding in a sequence. This might work nicely. I'll let you know, but nonetheless, I can still help you with a Porygon-Z trade.
To get Porygon2, you use the Up-Grade. It's on Route 15 somewhere. I just started exploring there, so haven't located it yet. It still needs trading with the Up-Grade.
Carnivine is located on Route 18 in B2/W2; just looked that detail up, and being able to trade backwards would get it into B/W as well if you have two systems (I think I read this is doable). Otherwise, it's found at Ilex Forest or Viridian Forest depending on the game you're playing in Gen. IV, and I'm not at either location or the Great Marsh/Safari Zone yet (Pearl and Platinum I haven't even kicked off officially).
Porygon-Z needs the Dubious Disc, which must be handed to a Porygon2 before trading it (it evolves on trading, which I believe consumes the Disc). The Dubious Disc is located at the P2 Lab off of the Route 17/18 area. If you have a Porygon2, head there and look for it, and I can help trade it back and forth as part of whatever we work out. In fact, I might want to borrow it for a moment mid-trade and pair it with my Ditto in the Daycare so I can get my own Porygon; this particular creature, as you probably know, is a White exclusive and this would remove it from my needs list. Heck, breeding anything like this on borrow would clear my list pretty darn quickly without having to produce new stuff to trade every time, as well. :D Would take too long to do everything that way, however. LMAO
If you don't have them available through HG/SS, no worries. We can do them in Black as well. Saves me transferring them later. I got an offer to help me out from someone in HG/SS, so I'm hoping that one goes through.
That would give me nine starters I'm looking to snare (ten if you want to count Pikachu, or something in its line; it WAS once a starter, after all). What could I trade that would be of interest? I know you said your Dex is pretty complete, but I can offer some SuperZoruas (I should trademark that). Two are in the box now, and I can breed plenty more. :D I can also hatch some Black swarms or other Black exclusives, like Murkrow. Let me know.