Wzor is claiming that the final sign off is set for July 13th. According to a translation, this is the final roadmap for Windows 7:

FINAL ROADMAP FOR WINDOWS 7 [CLIENT-SERVER]:

6/1 – 6/19 BUILDING RTM ESCROW – already assembled RTM ESCROW.

6/22 – 7/10 RTM RECALL – assembly and search for candidates to the final RTM release.

7/10 WINDOWS 7 RTM FINAL BUILD TARGET – build day “gold code”.

7/13 WINDOWS 7 RTM SIGN-OFF – the date of signing the final RTM release!

Via Neowin.