You need a Dante compatible digital volume control multichannel DAC that outputs XLR pre outs intended for amplifiers is the best way to handle Dante at this time.
I'll start by responding to your comment before I address your question.
This is essentially what the Tide 16, Marantz AV10-30, Anthem AVM70/90, Hyperion APR-16 or any other AVPs do but without resorting to Dante/AES67 but in some cases using analog volume control. They all include multichannel DACs with XLR balanced pre outs. Adding Dante/AES67 as a digital input source to a multichannell DAC with balanced pre outs doesn't change anything over using an AVP that has multichannell DACs with balancex pre outs. You're just moving the DACs around into another external box. In the context of home theater, the HDMI inputs are much more useful and the the facto standard.
Who said you need Dante to your existing speakers.
The reason why one may want to add Dante/AES67 into an existing speaker is the same reason that Dante speakers have been developed and exist. The crossover network is a very important component and a key contributor towards a speaker's sound quality. Everybody here knows this. My speakers for instance, while having good quality Scanspeak drivers are known for having a less than optimal crossover network. The design of a well performing crossover network to integrate the varying characteristics of each driver and their interactions inside the cabinet is not a trivial matter. You can take the best drivers, put them in a well designed cabinet and add a poorly designed crossover network and your speaker will end up sounding... well poorly.
An advantage of adding Dante to the speaker is keeping the signal digital in order to implement the crossover in the digital domain inside a DSP. This allows the designer to better integrate the different drivers in order go greatly reduce the spikes and dips and achieve a smoother, more linear response. Other DSP crossover advantages compared to traditional passive crossovers include no insertion loss, no power wasted as heat in resistors, and no added distortion from large inductors/capacitors interacting with driver impedance contributing to lower distortion and cleaner sound with tighter bass and better transient response. Another advantage is perfect time and phase alignment, something very difficult or impossible to achieve with passive crossovers, which improves imaging, coherence, and transient accuracy. There are a handful more of advantages of implementing the crossover design with a DSP but I'll stop here as my reply is getting too long.
As for disadvantages, like I said in my previous post, they're cost related with DAC/amplifier modules required for each driver. But as Amir's tests have revealed, you can get totally transparent DACs for about $100 and some excellent small amplifiers that are quite affordable. Then again, I wouldn't necessarily implement the Dante/AES67 strategy on all speakers, concentrating primarily on the L-C-R channels. For the surrounds and others channels, to keep the cost from escalating too high, I would be contempt with balanced analog outputs and if the processor only had Dante outputs, then sure, if a mutichannel DAC with a Dante input was available, that coul be used to feed the other channels.
Before the Dante/AES67 interfaces were developped, a handful of companies like Meridian produced active speakers with DSP crossovers, where the digital signal was fed into the speaker through coaxial S/PDIF. Today there are other many other companies selling active speakers with DSP crossovers that have various digital or wireless input interfaces, look at Kef for instance.