Hi hedgehognh3;
The P7M8 is usually pretty easy to carry, IMNSHO, since it's flat and compact.
Your described body size should permit you to use a shoulder rig (assuming a proper cover garment) with excellent concealment. Perhaps you've not used the right rig? I favor Lou Alessi's Bodyguard rig, since Lou employs a pull-through snap in the triggerguard of the P7 for retention (no infernal thumb-break tab!), which makes for a very compact setup compared to everyone else. If you spend lots of time driving or otherwise sitting down, a shoulder rig is ideal. You might find something pertinent in this review of shoulder rigs in this regard:
http://www.parkcitiestactical.com/shr.htm
As to belt holsters, both OWB and IWB, there are a few leathersmiths, notably Lou Alessi, Matt Del Fatti, and Ken Null, who do an excellent job with the P7 series, and one Kydex holstermaker, namely Gregg Garrett of Comp-Tac.
Because of the odd balance of the P7, it isn't very easy for a maker to get holster construction "just right" in a belt rig, but each of the above guys has it down.
On the other hand, there are several dozen makers (I've had examples of their work) who DON'T really know how to make a proper holster for the P7, but will be happy to try on your behalf for $. Stick with the above folks and you should be fine.
You'll note I haven't posted URLs for the above, but come over to Park Cities Tactical and do a search for "holsters" on Cult of the P7, and you'll find these plus "more than you ever wanted to know" about holsters for the P7 series. Best.