(And thanks to Ben for the original idea)
I've posted a rather simple application (with source code) up on Codeplex (http://remotewizard.codeplex.com/) that monitors a gMail account for a message with a TitanTV TVPI attachment. If the message is from a known good source (i.e. a name or phrase that we've designated that must be in the sender's email address), and if the subject contains a secret word (defined at program installation), the attached TVPI file is parsed, converted to Click-to-Record XML format, and submitted to Media Center using the CreateScheduleRequest method of the EventSchedule class in the Microsoft.MediaCenter.TV.Scheduling namespace.
For example:
1) On your remote computer, find a program you want to record in your TVTitan Program Guide
2) Click the listing anc choose 'Record:'

3) Save the resulting TVPI file somewhere handy:

4) Email the TVPI to the gMail account (that you should probably set up just for this purpose). Be sure to include your Secret Word in the Subject line:

5) The RemoteWizard will download your message, schedule your program, and send you an email confirmation:

6) Your program should now be scheduled in Media Center:

