Steve, G4RAW described this simple transmitter for 80 metres in Sprat 82 and describes how the World record for building a rig , actually a Oner, and having a QSO, is under 15 minutes.
The circuit shown above uses only a handful of components and the only adjustment is the 1000pF preset capacitor, which is used to attain the best note consistent with power out.
How quick can you make one and have a QSO? Say ten minutes to build and 5 minutes for a contact ... or less?
How about a little competition? Let me know what your time is and I'll put the results on qrp-l and gqrp-l!