The 16" will probably share the event with Mac Pro pricing and availability plus something else...
Any of these (maybe more than one?) could be featured...
1.) Some other MacBooks - either something really slim and light (in the old 12" MacBook niche), possibly with cellular, something "big and thin" (15" Air) or both. There are all those notebook model numbers we don't know anything about yet (and, under usual cycle times, they'd come out this year sometime). If Apple's really playing their cards close to their chest, some of these could be ARM (the 16" almost certainly isn't, due to software that won't run on ARM).
2.) New iMacs. The most exciting possibility would be a new iMac Pro based on the XDR display (or, more likely, a version of it with a somewhat less exotic backlight). The cost isn't as far off as one might think, because of quirks in Apple's pricing. Assuming the XDR is a 50% margin item (super high-end stuff can have that kind of margin), there are about $2500 worth of parts in there. Probably at least $300 and maybe $500 of it is the case (mostly), power supply, Thunderbolt chips, etc... That leaves the guts (panel, backlight, etc.) around $2000-$2200 in cost to Apple.
The weird quirk in Apple's pricing is that they'll take low or no margins on iMac displays on occasion, in order to produce iMacs with market-leading displays at reasonable prices. Both the original 27" iMac and the 27" Retina only worked for the first couple of years because Apple was essentially selling the display at cost (with the rest of the machine at a standard margin). If you put a version of the XDR display in an iMac Pro at cost (something like$1600-$2000, depending on how much they degrade the backlight), you have somewhere around $3000-$3400 for the rest of the Mac. 40% of that remainder is margin, leaving $1800-$2040 for parts. At Apple's volume, they can get quite a bit for that...
3.) New iPad Pros (and maybe other iPads).
