On boats with a bulwark or toerail, I've seen pretty bronze rollers set up on a bloc on deck directly inboard of the fairlead (don't really think this is a good plan, though). I've also seen similar rollers set right into the "notch" where the fairlead usually is (this is not as pretty but makes much more sense). Our Rawson 30 didn't have a bow roller (though it had a bowsprit, so could have easily had one there) but simply had the chain running from the anchor windlass out through the oval hawse in the bulwark. It worked fine, but we did have to manually unhook the anchor from its resting spot and drop it overboard.
SIDE NOTE: Now, if you're actually willing to lengthen your boat with a frame out there for a bow roller, why not make it worth your while to pay the extra slip length fee and consider adding a bowsprit (convert to a cutter rig?) which would be quite "traditional". Of course, you'd have to either work with a rigger or crunch the numbers yourself to figure out the requisite stay configuration to have both a headsail and staysail. This is likely to impact your aft set of stays and maybe your backstay. It would be a good excuse to add running-backs, of course
which are always a good "safety" net for a cruiser to have even if they're not used...The Rawson 30 original design was w/o a bowsprit but many were modified and later produced with them. Ours was a sloop, not a cutter, but had a bowsprit. To make it a cutter, the previous owner would have had to modify the stays and I guess he didn't wish to do so. If you make this mod, then you can have yourself a "self-tending" staysail in addition to your headsail. Just a thought. oh, my I'm digressing...
back to the main question of bow rollers...
Also, since your boat is "traditional" you might consider what is (I think) called a "cats-head" which is a pivoting arm with a bow roller at the end. It is usually used on boats with plumb bow (or for multiple anchors) and typically attached to the foredeck and when deployed it stuck out to the side over the bulwark (or in your case, toe rail); it must fairlead back to your windlass, of course. Quite "shippy" looking all in all. Our cruising boat has a plumb bow and has her anchor roller(s) on both sides of the 10' bowsprit. The anchors are deployed several feet away from the boat. With a system like ours, sometimes a "cats head" is still used to store the anchor rather than leave it secured to the bowsprit or bringing it back on deck from the sprit. Some people use a cats head (on power boats) right out there on the front of the boat since it can be flipped back onto deck. I can't say that I've seen a traditional sailboat with it used that way, though.
Nic Compton's "Great Classic Yacht Revival" has a lot of great photographs of classic (i.e. old and wooden) boats, mostly racing, but with enough detail that you can see rigging and deck hardware on many of the boats. I've found it very instructive since we are re-rigging our boat in a traditional manner and trying not to screw it up. There's a pic on page 130 of a cats-head being used to store an anchor off the side of the boat (in that case, the anchor leads out through a hawse forward of the cats-head and I can only surmise that there is another roller out on the sprit for use and they're just storing the anchor on the cats-head.
Good luck to you!