These were residential and day-schools whose purpose was to ensure that those children whose fathers were at the front, working abroad or who had died in battle would receive a formal education in line with NSDAP ideology and policy. Other children included into the programme were those from repatriating familes.
The Heimschulen were located within the Reich boundaries and according to the circular (dated 24.8.1941) which announced their institution they existed to provide a standardised education for the children of:
1. german parents who lived outside the Reich boundaries or who were on duty away from their normal place of residence for extended periods.
2. party officials, officers etc who, by virtue of their appointments, were away from home for extended periods
3. gifted children of farmers and manual workers.
Certain residential and day-schools were redesignated as Deutsche Heimschulen and by December 1941 there were 61 residential Heimschulen in existence with a further 7 residential and 20 normal schools being redesignated during 1942. Many more were to follow.
These were schools which, unlike the AHS/NAPOLA, were run in accordance with general school regulations so I would not think that any special uniform would have been introduced. I'm certainly not aware of any such uniforms.
1942 full list of Deutsche Heimschulen:
http://www.hj-research.com/forum/f85/deutsche-heimschulen-7025/