Do you mind telling us where one can find a congregatuion of these supposed jews who follow regular halachik judaism yet believe Jesus is the messsiah? As Ruth mentioned I have never heard of or met anyone like that, what I have heard of and known is along the lines of this:
The vast majority of Messianics are gentiles and are therefore less likely to grasp how to live a Jewish lifestyle. However, there are a handful of synagogues that are led by Messianic Jews who have been living a Torah-observant, Jewish life forever. I am sure that if you strolled into the first Messianic congregation on the block you would be repulsed by the patently Christian feel of the place. However, with some searching more respectable places exist.
I'm not here to push any views on anyone, but simply to get answers. However, since you apparently believe I am just making up hypothetical groups of people for the sake of argument, I'll post one link. http://www.omjra.org/ This is the Observant Messianic Jewish Rabbinical Association. They not only uphold written but rabbinical Law. They also do not advocate the worshipping of Yeshua, but simply the upholding of his teachings. There are many other sites, but again, that's not why I'm posting.