I like to play in low lvl PvP now and then, and create characters exclusively to specialise in 1 Rank. Example would be at Lt Level using a Runabout, where it is essential to use RSF and you need to be Lt 8 to get it.
This then only leaves you 3 grades in which to PvP before u have to create a new character to PvP at the same grade.
My Suggestions to combat this would be one or many of the following:
-Death Penalties made to include SP penalties (Not sure what their current decision is)
-An option to get no SP rewards from PvP
-Even better was if you could store a setup of your lower lvl ship and char so that you could for example: Save a Runabout setup with Mk II equipment and whatever Lt Skills you had chosen so that even if u rank up u can still participate in low lvl PvP
Also another minor problem with this is that some Traits are level restricted - Efficient is useless at Lt and LtC since the efficient skills are at Comm lvl.
I don't see SP as too harse a penalty but it would depend on how much of course - and in any case I guess for the few us that want to stay at Grade 10 of a particular rank it would be time consuming to keep suiciding.
You have a point about idea three it would mean a lot of coding, but probably the best option.
Another side note though - Maybe the Career Space power could be given earlier on - maybe at grade 3 so the window of PvP is larger (I'm sure its not just me that likes to have the most chance of winning).
Still doesn't lead to infinite PvP as an Lt though.