Well the cheapest XCD lens is the one that will do, the XCD90. You can get these second hand now on ebay for around $2000US or less.
HC lenses are the same price if you buy them new, but why would you buy them new? There are heaps of them on eBay. An HC80 would do the job and does not weigh much. I used that before I got the XCD90.
You will need to manual focus if you go the older HC route, but not a big deal for portrait as I would manual focus anyway.
Honestly though, at the end of the day XCD is the answer.
The only third party lens I use is the Canon TSE24 for landscapes.