i don't see how upgrading a bike through decals has any bonuses at all.
it makes the bike more desirable to a thief with base knowledge of what he is looking at, it opens the door to a potentially mis-sold bike further down the line, your also potentially going to look slightly desperate to those who might know what it really is (think of all the 'is it a zaskar' type threads we get from ebay purchases).
One exception to this (and i don't know if any manufacturers did it but i'm sure there will be some) is if the bikes were named & stickered up as different models depending on their original spec. to go with a slightly meat based theme here - beef cycles make just 1 frame - same geometry, tubing etc. but have the following groupsets on their 'range'....
rump steak - deore
sirloin steak - lx
rib-eye steak - xt
fillet steak - xtr
if you picked up an old rump steak frame, built it up on full XT to rib-eye spec then i suppose it could be acceptable to re-decal it.
one thing i would be in agreement with is down stickering - e.g if you use a zaskar for a commuter, re-badge it as an outpost and only those who see past a name sticker know what it is - but this still leaves you with the problem of a thief with knowledge.
why not go nameless and either completely ghost the frame, maybe with the exception of the headtube badge or just chuck manufacturer only rather than give it a model name - alternatively make up something of your own like the 'lime crosswork' already mentioned.