obviously we haven't been given this information yet, but by looking at BTO configurations for other macs, perhaps we can deduce them? I'm specifically curious about the upgrades to the stock 27" high end model (RAM, HDD/SDD options, CPU, & GPU) CPU: base = 3.2GHz quad i5 upgrade = 3.4GHz quad i7 best guess cost = $350 rationale = comparing it the upgrade cost for the 15" rMBP 2.3 quad i7 to a 2.7 quad i7, I'm afraid this cost might actually be more like $500 when it comes down to it bc we're going from i5 to i7 here. GPU base = 675MX upgrade = 680MX best guess cost = $200 rationale = this one is probably the toughest to determine as all the other macs with mobile GPUs have no upgrade option. However, looking at the Mac Pro upgrade options, we see that the ballpark is $200-$250. I'd venture a guess that apple will try to keep this price point if at all possible. RAM base = 8GB (two 4GB) 1600MHz DDR3 upgrade = 32GB (four 8GB) 1600MHz DDR3 best guess cost = $600 ($200 for each 8GB SODIMM) rationale = the 15" rMBP costs $200 to upgrade from 8GB to 16GB of the same type of RAM, this is probably pretty close to accurate pricing for the iMac as well. HDD/SDD options base = 1TB 7200RPM HDD upgrade-1 = 3TB fusion drive best guess cost-1 = $750 rationale-1 = in the Mac mini line, upgrading from a 1TB 5400RPM HDD to a 1TB Fusion drive is $250, I'm tripling this number and I think that's a conservative estimate (I'm sure the upgrade to a 1TB fusion is more like $250) upgrade-2 = 768 GB SDD best guess cost-2 = $1000 rationale-2 = in the Mac Pro line upgrading from (probably) the same 1TB 7200RPM HDD to a 512 SDD is $850. I'm wagering that to bump it to 768GB SDD is $1000 (apple likes round numbers) this is all speculation obviously, but it's looking like a fully upgraded BTO 27" will be something like $1999 + $1000 (768 GB SDD) + $600 (32GB RAM) + $200 (680MX GPU) + $350 (3.4 quad i7 CPU) = $4149 pretty sure that's a lowball number too.