Welcome, we're glad to have you here with us.
It is always heartbreaking to hear about someone's loss. Most of us have been through that experience, and your experience brings back the emotions we went through at losing Rocky.
While the Boxer's life expectancy is shorter than many breeds, they manage to cram more joy, love, attention, activity, humor, and life into a home in that period of time than other dogs who live twice as long.
Consider a white Boxer pup. There are many reputable and responsible breeders who are "white friendly". Most are members of the American Boxer Club, and one of the club rules prohibit the selling or registering of whites.
You could offer to pay a proportionate share of the cost of having the litter which will vary depending on the size of the litter along veterinary and other expenses.
Other than a higher incidence of deafness at birth, statistically they can be expected to experience no more health problems than their litter mates of color.
They are not rare. Twenty to Twenty five percent of Boxers are white. A white Boxer by definition is one whose body is more than one third white.
When you are reacy to consider adding a pup to your household, attend some dog shows. They are a wonderful place to meet breeders. They can also point you to other breeders.
You will be a lot less likely to deal with an backyard breeder if you go that route. You will definitely be avoiding the puppy mill experience.
Keep in mind, that while a puppy may be "expensive" from a responsible breeder, the chances are that he/she will be more economical in the long run since you will be less likely to experience many of the maladies common to the breed.
There will always be exceptions, but you will be much more likely to end up with a healthier dog with fewer allergies.
Visits to the vet can quickly make an "econo dog" more expensive than a "quality dog".
I know how empty your home must seem. Believe me, another Boxer will once again bring life and joy to your home. It will not replace Dharma, nor would you expect him/her to. But they will restore the atmosphere that so endeared Dharma to you.
Tom