Talk to Lava Louie, tell him Karen sent ya. Ask for Michelle first. She's Louie's sister and will get Louie to the phone or makes sure he calls you back. Be sure to tell her Karen refered you. I have a super relationship with the Louie and his sis.
Louie makes BIG commerical lava lamps. At least 1 installation I know of was incorporated into a wall. Louie makes super goo in beautiful colors. You can buy the goo and surficant from him and, I'd ask the worst thing he can say is no, maybe even the glass globe(s) and heating base(s) and good advice too.
Louie is the King of Lava and a true delight to talk to and work with.
You may hear or read some complaints about Louie comma but the complaints are not about the goo but about the long wait for shipping post order. Well the days of the "long wait" with Louie are over and I can attest from experience his goo is the tops and the colors rich and vibrant. His violet is to die for. I'll post some pics of my Louie goo Grande re-fills when I retrieve my camera from my daughter's house.
Karen knee jerk reation thoughts about your desired installation
A 5 foot horizonally placed single glass housing, I believe, would not work, I don't believe it would give you the desired goo flow result and you need solid glass. a fish tank type is 4 pieces of glass glued together, 4 stress points for real hot liquid would be disaster waiting to happen. COMMA BUT you can make an amazing 60 inch long , 48 inch high in wall lava installation with several large cylinder glass globes. I would do it so the lava is seen on both sides of the wall and house the lava's in a cut out "hidden" door type thing. You will need easy access to the lamps for changing light bulbs etc so the "wall" you have them behind will need to open and close on one side. Use hidden hinges all that and the "door" will look like a "wall". The extra added benefit of using several globes gives you the option of using one or several different colors of goo in the installation.
Louie makes goo kits in pint and quart sizes and sends them UPS for you to put together so cloudiness is not an issue at all.
You get oil based goo in a mason type jar, it comes white. You get oil based goo color and a surficant to add to distilled water and instructions. Easy as it can be and waaaaaay cheaper than buying 8 32z or 5 52z lamps to do a grande refill. Cost is about $40 to do a Grande with Louie goo, including the distilled water, vs $125 or more to buy 5 52z lamps. You will have a nice range of colors to choose from and you choose the color density with how much you add. http://www.lavalouie.com/ecom/stores_app/Browse_dept_items.asp?Shop...
Taking the cap off is a bit of a pain but nothing difficult about it.
Take a very thin blade knife and little by little, easy does it so no tearing if possible, slide the thin blade under the little alumium lip between the base of the cap and the glass.
Others do the rest differently and probably better so the rest is how I do it. Bohdan and 6 feet under and other masters can give you excellent instruction.
I slide the knife all the way around, little bit by little bit, until the cap comes off. Under the cap is a plug. Pull the plug out.
My goofball method of securing the plug and lid after re-fill is goofy but works. I will not confuse you with my methods.
There are tons of forums on the subject and Bohdan is the Master.
You replug when the lamp is cold.