Revised for tennerman:
Again, while I appreciate the Vikings allusion, I don't feel it is nearly that lopsided of a trade, especially for a top team that continues drafts low in the draft.
Consider what many on here was the most lopsided trade in history. Pau Gasol was traded for Javaris Crittendo (a rookie 1st rounder), 2 first rounders, and Marc Gasol, who was the MVP of the Spanish League and ended up being on the All Rookie team, and would have been a lottery pick had he not already been drafted (plus a lot of cap space).
So Carmello for 5 first rounders is lopsided in the Nuggets favor, but Pau for 2 first rounders, a rookie first rounder that they would flip for a first round draft pick, and Marc Gasol who was at the time a dominant player in his league and ended up on the All-Rookie team and cap space is incredibly lopsided in the Laker's favor?
To me, if a team like the Mavericks actually had 5 draft 1st rounders to trade for Carmello, they would need to strongly consider that deal (if they were guaranteed the extension).
Moreover, since a team is not allowed to trade consecutive draft picks (1st round) and are only allowed to trade draft picks up to 7 years in advance, it would be impossible for a team to trade 5 first round draft picks (although they may be able to creatively do so).