The thermistor would have a high start up resistance, which would drop as the bulb warmed up, limiting the startup rush current. Thermistors are still readily available from 'electronic kit part' places fairly cheaply - Tandy Electronics for example, if they still exist.

You may wish to read this article

The Case for CFLs
http://www.slate.com/id/2183606/pagenum/all/#page_start