Thanks for the comment guys.
I have already placed an order for keycaps from Unicomp, it cost only $20 for 101 and 104 keyset; wonder why its so cheap, it cost even less than thin ABS keyset for Cherry MX mount; is it still Thick PBT like the one coming from original Model M ?
And with the case, at the moment I tried contacting Unicomp for the replacement, they said they only offer brand new Unicomp case. While clickykeyboards.com also do not have such part in their product list, but I have already send an e-mail and is currently waiting for their reply. From where I live (Thailand) there is only one source where you can obtain Model M keyboard, which is government auction- and all of them will have their serial number scratched off.
Also with the keycaps clickykeyboards now only sell single key, not whole keyset; so ordering 101 of them would cost $101 without shipping. So basically Unicomp is the only choice here lol.