no. we still swap upgrades all the time. i probably do it 3-4 times a day, its built directly into our PoS (point of sale) system and i don't see that feature going anywhere anytime soon.
as for the unlimited data part, yes even if you use an upgrade from another line you are getting a subsidized price on THAT number so the SYSTEM makes us choose a data package during checkout...
NOW the EASY way around that is to just use the upgrade on the line the upgrade is for and then do a device swap... put the original phone that was on the line with the upgrade BACK on that line and then swap the new phone to the line with unlimited data and it will be considered CPE (customer provided equipment) at that point and will NOT force us to change the data... but if anyone asks you didn't hear that from me