Let me start by say I make nothing from this endorsement - No financial gains will be made by my post. I have included a lot of what I consider to be good solid advice and not all will agree with me.
Well, Don Robinson makes some high quality linerlocks (3-1/2 inch Linerlock Barlow that can be made larger and likely the blade can be modified) and uses titanium liners. He makes precison linerlocks using precision pivot pins that fit in a bronze-phosphorus bushing. I bought several different sets of his plans and I like what I see. Don only buys the precision pivot pins and he makes everything else. Don can make anything you want.
http://home.earthlink.net/~donwrobinson
I hear he's a good Christian man, so he may also be of help finding a knifemaker who will do it for $400.00. But, I recall his prices
start at $375 or $400.00 for a linerlock.
Linerlocks are a lot of work and titanium (6Al-4V alloy) is actually the best way to go about it. His phone number is in the website, many of the knives that are more than $400 have filework and engraving. Even if you don't buy from Don, I do reccommend talking with him.
BUT he is a tool and die engineer and can make anything under the sun. If he can't fit your price range - I think he could probably recommend someone who can.
If nothing else, you would get a lot of good advice and
if you are willing to go to $400.00, consider an extra $100 to $150 to get close to EXACTLY what you want. In that range, if you compromise too much you won't be happy with what you get. I realize there is a cut-off point but liner locks are a lot of work.
From my point of view, $400 is a lot of money and for that much money, too much to do a lot of compromising, BUT don't break the Bank. That is a very fine line to walk because once you buy the knife - it's yours and it would be a very sad thing to spend that much money and be unhappy. It's not like you can divorce it!
On the other hand if you get exactly what you want - it will last your lifetime and you will always be happy when you look at it!
SO, yes at $400, IT'S VERY important that you are completely happy with your purchase.
Listen with both your pocket book and your heart, DON'T break the bank and DON't compromise your dream knife AWAY! There is middle ground to be happy -
BUT just like are financial limits - you also need to set limits as to how far your willing to compromise. Know BOTH before you start.
I hear Don likes to know that his knives are being used. He also uses both a Mill and a belt grinder to make his blades. He heat treats his own blades and does cryo - I think (memory thing - again
).
With that said - there is a definite cut-off point. But I will say it again. Buy a knife that will make you happy, even if it's a $100 or $150 extra. $400 is a lot of money - so don't cheat yourself --ROB yourself of that pleasure of buying a knife that you help design by talking with the knifemaker. The pleasure you will have being a part of it is priceless. Remember - this is a purchase of a lifetime, you may never buy another - SO, you want a positive experience!
I picked Don because I bought his plans (all his knife plans
bought and watched his DVD - 4 times now and I have not fallen asleep). It is a 4hr DVD (2 DVD set) and you can rent it from Smart Flicks. I also picked Don because he won't steer you wrong and with his background and experience - he really can make anything. Also, I've NEVER heard anyone say anything bad about Don. Don is a wealth of information.
I realize I've repeated myself many times about compromise vs. an extra $100 or so because I believe it is a very important issue to consider. Likely it is your most important issue that must be decided.
Good Luck and let us know who you chose AND definiely show it to us!
That was many knives ago! Someone came to the shop and bought that because I didn't have any knives to sell. 
