I'd like to share with you my opinion and personal experience with the Honda Jazz.
When the MMC Jazz 1.5V came out last year, it was priced at 857K, about 15K higher than the pre-mmc * 842K. The main competitor of the Jazz (in my opinion) is the Ford Fiesta 1.6 Sport which was priced at 816K I think. so the variance you pay for the extra versatility of the Jazz was only 41K. Pricey but manageable.
Now the JAZZ EX * 899K is a bit too much already thats about 83K or 10% more of the price tag of a Fiesta Sport. sure they added cruisecontrol, audiocontrols, a/c glovebox but removed the disc brake (wth?) and the RS bodykit. Clearly not worth it if you ask me. Yes, its CBU Japan but I'm pretty sure they have Japanese standards in their Thai Plant so I'm assured the quality is the same where ever it was built.
As for the Rio, I'm not so impressed, It's a 1.4 and priced more expensive the Ford Fiesta Sport with about the same features. So I'll pick the Fiesta anytime over it.
As for the body kit... are u really going to spend more money on that after getting a Jazz priced * 899K ? If ever , I'd get the Mugen Body kit nalng. Mas maganda pa kesa the RS body kit last year's jazz had (ofcourse since its an aftermarket add-on). Expected to spend around 40K for that.
As for the waiting part of your story, I can perfectly relate hehe frustrating talaga. same thing happened to me when I purchased my MMC Jazz 1.5 last year. Imagine, I ordered last week of March 2011. Dumating ung Jazz ko 3rd Week August. I waited for about 5 months for it. They said the same thing, June then it became July and I was really almost going to give up and get a City but my Agent told me, August na talaga just wait. I had to really think bout it since my car will be my car for years. dapat no regrets. I waited for my Jazz and I'm really happy with her. No regrets. Definitely worth the wait coz na gustohan ko talaga ung MMC body kit which is the same body kit Honda FIT RS has. (top of the line na Jazz in Japan)
In conclusion, my advise if you can wait for the Thai plant to open up get the Jazz with the RS body kit. If not, I think its better to get a Ford Fiesta Sport than get the Jazz EX * 899K