Both my IP-057 and IP-033 have an inner liner for each of the internal cable runs, push the cable or brake line in one end, it glides inside the frame and pops out the other end. I would suggest running the line from back to front, just easier that way.
On MTBR, someone posted a picture of the IP-256 and it has a removable plate on the bottom bracket for access to cable routing. I'm not sure what to think about that at the moment. Could be fine, could cause other problems.
The FR-225 is a Flyxxi frame, not sure how nice the routing is on that frame. I know some posters on MTBR have complained about having problems with the cable routing on the Flyxxi frames, needing to drill out the holes to run the cables they way they want, with full housings.
Have you looked at the XMIplay IP-033? Seems like a similar hard tail frame with nice looking lines.
I have no issues with internal routing on either of my frames, if I needed to replaces cables, it would not be any more difficult for me to do than if the cables were external.