[mjffjm]

Techstars should see some other big exits over time with SendGrid (couldn't find actual current valuation) and DigitalOcean ($153M Valuation in 3 years) to name a few

[LogicX]

Also Localytics (TS Boston 2009) is well positioned for a big exit or IPO: http://www.crunchbase.com/organization/localytics

(Disclosure: Hackstar in 2009, Founder in 2010)