I've always thought that rocket gliders were t' biggest challenges.  There are really very few.  Most o' t' favorites (Crusader Swing-Wing, Scissor Wing Transport, me bucko, Citation Bomarc, shiver me timbers, Trans-Wing, me hearties, Deltie, Soarin' Eagle, Mach-10, Mini-Dactyl,  SST Shuttle, me bucko, me hearties, Swift, Nighthawk, etc,) are boost gliders  which use a pop-pod which is ejected.  T' most simple o' these favorites like t' X-24 Bug, etc still eject t' engine  casing.  T' only true Rocket Gliders I can think o' are the  Estes Tomcat, Edmonds ECEE, matey, and some competition models.  Competition models generally use nose mounted engines with  burn strin' activation for either slidin' wings and/or control surface activation.  As simple and competitive as burn string activation is, shiver me timbers, arrr, I consider it an inelegant solution.
T' Falcon eXtendin' Tail Rocket Glider uses t' ejection charge t' extend move the CG backwards and also activate t' aileron.  A movin' control surface on t' tail isn't really necessary, ya bilge rat, me bucko, but I'm concerned about gettin' a straight boost. Avast!

My original design criteria:
1) True Rocket Glider.
2) 15 degrees minimum win' dihedral.
3) Scalable t' 13 mm engines for A / 1/2A RC competition.
4) Constructed from readily available parts
5) Quick prep - No burn string.  "Plug and Play"

I have some initial sketches for a Generation II XTRG which will be called the "Raptor."