How about a Lemon-Launcher? it is either a mortar or a grenade launcher (as in RR's sticky grenade launcher) that fires Irradiated oversized weaponized lemons that explode on contact with an acid burst (like when batteries die)
On those same terms, why doesnt LK stuff have more acid explosions? or lemon shaped munitions... seems fitting.
Also, How about a baghdad battery? You know, power fueled by lemon juice. They could be LK's small battery 1x1x2 tall with a small capacity, but fast recharge.
also how about a Lemon Juice Cannon, a lot like Rafs' GT Hydro cannon, but it deals acid damage as well as knockback but with yellow colored water effect.
lastly, howabout the Zest Engine, in line with the Hawkeye rate of fire engine, and the Venture dragster engine, But LK's version significantly boosts the carrying capacity and traction of tank tracks at the cost of over-torquing normal wheels and making them lose traction. i dont see a necessarily 'lemon' theme here, but it jives with the bulky feel of LK and could do magical things for big LK Baneblades. (Super tanks, for those not 40K innitiated...)
Edit: Second afterthought (put here because of engine idea.) OR LK Zest Engine could add acid splash damage to all ballistics. wouldnt that be fun?
Afterthought: The juicer. A bigger badder Cerberus drill sized for LK. it could even be laced with the powerful lemon derived acid mentioned in my previous ideas.
Anyways just food for thought. Get the creative juices flowing, you know.
ill stop making puns now.