The Hama photometers are nice, but are still single and not multi photometers - so you need to buy one for iron, one for nitrate and so on. At last you will end up expensive.
The Wasserpantscher photometer ($140-170) is a multi photometer and as far I know they have test kits for it: Mg, nitrate, potassium, chloride,phosphate, co2, ph, nitrite, kh, ammoniak, silikate, O2 (and certainly iron).
From Söll there is also a Multiphotometer availible: http://www.aqua-check.de/en/
I personaly never buyed those photometers, so I cant say anything about it.
I still know most ppl.in Germany buy photometers to check their potassium levels in planted tanks, because there are no potassium test kits around from JBL, Sera, Tetra or so.
I personally use a DIY Kalignost test for testing potassium levels and doing so works pretty fine without photometer.
Since I am mixing my own fertilizer, I am certainly somehow interested to test uptake rates from stuff like zn, cu, boron - unfortunatly there are no affordable photometers around which can measure each stuff.
I'm not sure we can get that iron test kit you have in America.
I am not sure, I think you need to ask them - perhaps they will ship the iron test kit abroads?