my guesses:
$1099, $1299, $1599, $1899 (macbook: base, mid, high, high fully-loaded)
$1799, $2099, $2299, $2599 (air: base, mid, high, high fully-loaded)
$2099, $2399, $2699, $3099 (Pro: base, mid, high, high fully-loaded)
i don't see this happeing because 1. there is a lot of talk of them lowering prices on all the models, and 2, why would they have 4 different models? i think three is more than enough