Historically, there has perhaps always been this question of the validity of taking the various portions of the Nevi'im and writing them together into a sefer. In Gittin 60, Rabah and Rav Yosef hold that it is usser to write anything but complete sefarim of Tanakh. Mar bar Rav Ashi even holds that such a sefer is muktzeh because one is forbidden to read from it. The halakha, however, appears not to be according to these positions on the grounds of eit laasot laShem, because the purchase of a complete set of navi on klaf would be beyond the financial means of a tzibbur. Taz and Magen Avraham hold that in our days since printed Nevi'im are inexpensive eit laasot laShem no longer applies.
Despite this, there appears to be in recent years a growing trend to write sifrei haftarot on klaf. I became aware of one commissioned by the FJMC (Federation of Jewish Men's Clubs) in 2003, which travels on a weekly basis from synagogue to synagogue across the US.
Each of the Haftarot portions appear in order with the title, trope marks and nekudot written in by the sofer.
In this particular sefer haftarot under the title of each portion is inscribed the name of the group which sponsored the writing. Note also the taggim are omitted presumably to allow for the insertion of the trope marks.
There are even "sofrim" who offer illuminated haftarah scrolls as the one seen above which enlarges and illustrates the first word of each haftarah.
As a variety of sifrei haftarot handwritten on klaf are becoming more and more common not only in reform and conservative temples, but even in a number of Orthodox synagogues both in the US and Israel, it occurs to me to ask what is the halakhic status of such sifrei haftarot?