One older design I posted on solaris7 (can't figure out their current design) was a semi-mobile field gun style. Essentially a wheeled or treaded vehicle with a Gauss Rifle in the Forward mount. No turret, sides and rear had ~10 pts of armor each, the front had ~200 pts. If you try to engage from the front in a slugging match, hope for crits.
Another design they had on Solaris7 was the Obsidian Idol. 100 ton Clan Omni with every Mech tech it could tossed on (Endo-steel, DHS, XL engine, and FF too IIRC). One of the designs had four Gauss Rifles on it, and a comment read, 'Dear god, the Clanners hired a Lyran'.
One fun set of rules I had there was population estimates in the periphery. IIRC is was like:
Start:
Table 1:
1 - 1000 adults
2-6 - roll on table 2
Table 2:
1-2 - 10,000 people
3-6 - Roll on Table 3
Repeat that until you get the last table where only rolling a 6 gave you the max base population (100 million people).
You then multiplied the base population by:
1 - 1
2 - 1.45
3 - 2.15
4 - 3.15
5 - 4.65
6 - 6.8
My theory was that you would need at least 500 couples to keep enough genetic variation to avoid long-term inbreeding, and the multiplication formed a nice curve to increase to the next order of magnitude. Children are not included, allowing the GM to have a nice story. There were other die roll modifiers so you could allow for proximity to other high-population worlds, and similar. Lost a lot of stuff when that site went down