The amount of Hello Kitty religious tat on the market is not limited to the unofficial, it seems. For example, here is a Hello Kitty Cross Rosary pendant for sale on a Japanese Sanrio web site. The cross is about 3.0 x 3.2 cm in size and is made of sterling silver with a rhodium finish. Four cubic zirconia stones are placed in the centre of the flowers. It comes with a 50cm chain, and costs a mere ¥9,800 (approximately £45).
But that's not all. Look what Hello Kitty Hell found: a blinged out Hello Kitty cross, with diamante everywhere and a Kitty head that swings in front. No news on whether it sings Always Look on the Bright Side of Life, but it ought to.
But Kitty's for everyone, not just Christians. Again, unlikely to be official product is this Hello Kitty yarmulke:

I'm forced to wonder if these products are deliberately satirical or if the Japanese company that options these products might lack a concrete grasp of their implications.
The Japanese have an interesting attitude to religion - they use it for rites of passage, but don't seem to actually believe any of it, and will choose what they consider to be the most appropriate faith for the ritual concerned. Most baby-namings in Japan will involve a Shinto ceremony; for weddings, a Christian ceremony is currently fashionable (mostly because of the frocks, as far as I can tell) and funerals are Buddhist, because everyone knows Buddhism has nothing to do with the here and now. And they have no trouble whatsoever with things like this.