[Possum]

I do it just like Q said. I use arabic numerals for combat ships, changing to a new number for a major upgrade, or adding a lower case letter suffix for a minor upgrade.

I do support ships the same way, but I use roman numerals for them.

I am a big, big upgrader. I build frigates with a repair bay and 2 engines, and leave them sit at major bases for fast repair capability. It's not at all unusual for me to have a per-turn repair capacity of 40-50 systems at a forward base.

I tend to build bare-bones combat ships, using only the absolutely essential systems - engines, sensors, weapons, armor, shields. For this reason, I build a lot of support ships, and I tend toward somewhat specialised support ships.

To a certain extent, this helps with upgrades, as the systems that need upgrading are often on a support ship, rather than on the combat ships themselves.