They are available but where to get one BATTERY operated?
Can I get some basic laser and change optics (I have no clue on lasers…)?
No need to be powerful, 5-20mW is plenty. Run time should be pretty good…
You can get a laser with a 12mm lens and pop the lens out and replace it with a glass line generator lens easy. Basically it needs to be a quality laser. Most of the cheapies have random lens in them so its not guaranteed to have the 12mm lens. Most dont even have removable lens, they are glued in place 
Any suggestions for such host?
16340 or 18650 battery capability would be nice.
What wavelength are you desiring and are you willing to build it yourself or do you want to buy it complete?
Also what is the use for this, that will help determine the wavelength.
There are zillions of them on Ebay… also many different patterns (crosshairs, targets, circles, etc).
It will be a targetin laser for large brake press.
Color is not important, what we use now elsewhere are red.
I would pefer to buy them ready but not sure if they are available.
There are tons of laser line generators in eBay but one that needs PSU won’t do. It has to be batteryoperated. The ones I have found have only spot beam
I’ve seen “laser” rear bike lights that seem to project 2 parallel lines on the road. Those are battery operated at least, so that should be possible. This is an example with pictures (I don’t have any experience with such lights and don’t know this seller, just posting this link for the pictures):
http://www.ebay.com/itm/5-LED-2-Laser-Safety-Cycling-Bicycle-Bike-Flashing-Light-Lamp-Rear-Tail-Red-Beam-/370848484962?pt=LH_DefaultDomain_0&hash=item56584ace62
I think it should be just a single line, metal casing would be almost a necessity in work enviroment…
O-Like carries them, like this one :
Just the module tho, have to supply your own battery pack. 635nm is a nice bright red.
Metal case , 20mw . The lens/ retainer may be plastic though …
There may be better industrial grade stuff out there … you didn’t mention a price ?
UPDATE!
There seems to be no ready-made options for Laser Line generators operated by battery with pretty long runtimes.
We will try to build ones for ourselves at work.
Host is going to be a Solarforce L2 or maybe L2T. Square body may allow easier attachment of support/magnet holder etc.
I will order basic 5mW laser line generators, rest is modding.
Help I need:
- we are planning to buy empty pills in which to mount an empty driver board as a positive connection. Then solder wires from there to Diode.
Are this kind of "drivers" available, they need just to be contact plates?
Recommendations how to do it?
Laser diode component will likely be fitted to aluminum/iron housing which then screws to brass pill with driver or contact.
Then the assemble will be fitted to Solarforce host.
These are the modules:
http://www.ebay.com/itm/130982108805?ssPageName=STRK:MEWNX:IT&\_trksid=p3984.m1497.l2649
There are some contact plates around. $0.75 21mm contact plate. You can also disassemble a tailcap switch to use its contact plate.
That ebay module say it needs 4.5-5v though.
Oh bugger….
If that is correct, I need to get other ones to replace 
Can a 3.2V VDC one take the 4.20V from 18650??
http://www.ebay.com/itm/650nm-5mW-laser-module-3-2VDC-line-generator-650-nm-/380437723328?pt=LH_DefaultDomain_0&hash=item5893daf8c0
If the listing doesn’t say or give infomation on the driver, there is no way of knowing.
They do sell the line lenses in a few different degree angles. You could get a low power laser meant for small li-ions, use a 18650 instead & mount a line lens on it. AixiZ Line Generator lenses
Ok….
Got the parts BUT:
It seems like eBay sellers sell “3V - 5V” modules which don´t actually work with single 4.2V battery….
Any ideas which driver to use to get the voltage up to 5V or thereabouts?
Giving it a bump…
Still in need for help about drivers.
I got a refund from eBay seller. Wrong specs in description.
Basic laserline module, couple of bucks.
L2T.
Empty dropin.
Some NANJG drivers ripped to zero SMD components, epoxy clue and thats about it.
Made 3 for my company for working purposes.
Cool project! Nice to see you come through on this one.
Whats is the throw on these 
those modules that .9vdc to 4.2vdc and bump it up to 5vdc for charging USB
There is a laser pointer forum that does some CRAZY stuff with lasers!