According to the IDA Equipment Search List, it seem to be only Non-LTE version of HTC One X+ model will be launched in Singapore at the moment. It is proven that IDA Equipment Search List has high reliability since in earlier of this month, only Galaxy Note 2 LTE is captured in the list and eventually turn out to be true. If you are planning to get the 1.7GHz HTC One X+ in Singapore, you may suffer from the unavailable of 4G high speed connectivity.
We have no further information on this issue until HTC Singapore officially announce the availability of LTE version of HTC One X+ in their website or Facebook page. Stay tune.