Sure, you are going to want active cables, to cover that distance, the 70 footer is going to take 2 cables as they don't have a single cable that long. http://www.monoprice.com/Category?c_id=102&cp_id=10255
To put them together you well need a coupler and I think with the active cables there won't be a problem. I have used these without one in my home a few times and I have used a lot of Monoprice products with out a problem of any kind.
You can also do this with nonactive cables
http://www.monoprice.com/Product?c_id=102&cp_id=10240&cs_id=1024002&p_id=2893&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FCategory%3Fc_id%3D102%26cp_id%3D10240
And 2 of these
http://www.monoprice.com/Product?c_id=102&cp_id=10240&cs_id=1024002&p_id=2805&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FCategory%3Fc_id%3D102%26cp_id%3D10240
The 22awg are very stiff so these are going to be need.
http://www.monoprice.com/Product/?c_id=104&cp_id=10419&cs_id=1041913&p_id=2891&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FProduct%3Fc_id%3D102%26cp_id%3D10240%26cs_id%3D1024002%26p_id%3D2805%26seq%3D1%26format%3D2
You have not specified how you are going to get the video from the iPhone to the splitter. I am assuming you have a docking station that has an HDMI output; so one of the 2 splitters well do the trick.
but don't forget the cable from the doc to the splitter.
http://www.monoprice.com/Product/?c_id=101&cp_id=10113&cs_id=1011307&p_id=7618&seq=1&format=1&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FProduct%3Fc_id%3D101%26cp_id%3D10113%26cs_id%3D1011307%26p_id%3D7618%26seq%3D1%26format%3D2#largeimage
http://www.monoprice.com/Product?c_id=101&cp_id=10113&cs_id=1011307&p_id=6192&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FCategory%3Fc_id%3D109%26cp_id%3D10113%26ref%3Dcj
To put them together you well need a coupler and I think with the active cables there won't be a problem. I have used these without one in my home a few times and I have used a lot of Monoprice products with out a problem of any kind.
You can also do this with nonactive cables
http://www.monoprice.com/Product?c_id=102&cp_id=10240&cs_id=1024002&p_id=2893&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FCategory%3Fc_id%3D102%26cp_id%3D10240
And 2 of these
http://www.monoprice.com/Product?c_id=102&cp_id=10240&cs_id=1024002&p_id=2805&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FCategory%3Fc_id%3D102%26cp_id%3D10240
The 22awg are very stiff so these are going to be need.
http://www.monoprice.com/Product/?c_id=104&cp_id=10419&cs_id=1041913&p_id=2891&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FProduct%3Fc_id%3D102%26cp_id%3D10240%26cs_id%3D1024002%26p_id%3D2805%26seq%3D1%26format%3D2
You have not specified how you are going to get the video from the iPhone to the splitter. I am assuming you have a docking station that has an HDMI output; so one of the 2 splitters well do the trick.
but don't forget the cable from the doc to the splitter.
http://www.monoprice.com/Product/?c_id=101&cp_id=10113&cs_id=1011307&p_id=7618&seq=1&format=1&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FProduct%3Fc_id%3D101%26cp_id%3D10113%26cs_id%3D1011307%26p_id%3D7618%26seq%3D1%26format%3D2#largeimage
http://www.monoprice.com/Product?c_id=101&cp_id=10113&cs_id=1011307&p_id=6192&seq=1&format=2&utm_expid=58369800-11.R-enhtUGRrSdHz5vzpVS2g.0&utm_referrer=http%3A%2F%2Fwww.monoprice.com%2FCategory%3Fc_id%3D109%26cp_id%3D10113%26ref%3Dcj