Looking specificially for the lighted forearm, rail system, or front vertical grip?  Can't find them anywhere!

I am pretty sure that these are not available from anyone at this time. Monolith had a front PS90 type grip and also a front rail system but I think these are on hold while they work out some business dealings.

The lighted forearm you can make yourself by taking the rifle down for cleaning, removing the forearm and separating the clamshell into two pieces you'll see the ribs with a semi-circular area that can be cut down. You can then cut the molded plastic ribs with an x-acto knife to a diameter suitable to fit your desired light. There's also a small relief gap on the bottom of the forearm light where the wire for a tapeswitch can go.
Supposedly you can get replacements for the forearm from FN but I've never tried.

I bought my PS90 style railed forearm from monolith arms last year, it's fantastic but again I don't know their current situation regarding sales. You could email them and see or you start posting a WTB ad on the various boards and forums.

From the shot show threads, apparently FN has some nice forearm replacements but who knows when they'll be available.

Don't hold your breath on the rail.  Monolith was supposedly bought out by Magpul and will make the tri rail, although no one from Magpul has confirmed this yet.  Now FN on the other hand, has had the tri rail has an available part in the FS owners manual from the first FS sold, but yet no part has surfaced for sale.  

Basically, just do the flashlight mod in the stock handguard and sit tight and wait for someone to step up and offer a tri rail.

I've been trying to make some polymer molds for tri rails but finding it very difficult to make the 1919 rails metal.  The initial polymer molds have turned out to be very time consuming, and thats with my roomate who does polymer molds everyday trying to make them.

I'm not sure what you mean by "trying to make the 1919 rails metal".

Just do it the simple way and have a relief area on the inside where you attach a backing plate to mount screw-on rails. Unless I'm misinterpreting something.

FN is so frustrating.....they release some truly amazing new firearms but the after sales support (parts kits, existing accessories, components, etc) are as scarce as hens teeth.

I love their weapons but damn, throw us a bone here.

We used the monolith version 1 rail as a starting point and those rails were actually polymer.  Tried to do the same and the railing just snap when I tried to put a vfg on it.  I have no idea how the work with the polymer molding so my buddy is trying to make the actual bottom rail with a metal tab railing that will slide in.