I rode my bike out to Reston (admittedly not Tysons) this past weekend and it looks like construction has begun on the Block 16 parcel, located next to the Rolls Royce bulding at the Reston Town Center.
Image courtesy of Asadoorian Retail Solutions:
http://www.asaretail.com/properties/...n-town-center#
Here is a description of the development:
Lend Lease Selected by Boston Properties to Provide Construction Management Services for New Luxury Residential Building
http://www.prnewswire.com/news-relea...137011418.html